The present invention relates to a programmable network in which in a network system interconnecting a plurality of computers via a network, a program is loaded to a network node on a route of a flow constituted of packets, and the node executes the program for each packet.
For a network system in which data is processed and then transmitted, a method is known by which a video is compressed and packetized for each wavelet band, as disclosed in JP-A-7-15609. The invention provides a video transfer method, a video transmitter, a video receiver and an video transfer apparatus, in which a video is transferred in accordance with a network bandwidth on a video reception side and a decoding capability of the decoder, even if which capabilities are inferior to a network bandwidth on a video transmission side and an encoding capability of the encoder. The video transmitter packetizes video data for each wavelet band, adds a predetermined classifier to the packet, and then transmits it. If video data transmitted by ATM (Asynchronous Transfer Mode) network, a priority order is added to a cell header to transmit a cell. On the network which transfers video data, a cell having a higher priority order is transferred with a priority over other cells when the network is congested. The video receiver checks the classifier of the received video data, selects only necessary video data and decodes it in accordance with the decoding capability of the decoder to reproduce the video data.
A programmable network is known as described in "A Survey of Active Network Research" in "IEEE Communications Magazine", January issue of 1997, at pp. 80-86. In the programmable network, each network node constituting the network executes a packet processing program for each packet. For example, the above-described transfer with a priority order by ATM is realized by software using a program loaded at each network node. This system can be realized on the network having a QoS (Quality of Service) control function of ATM, e.g., on an IP (Internet Protocol) network such as the Internet.
For the IP network, techniques are also known by which a routing process for controlling a route of packets via network nodes can be speeded up by using a dedicated processor.
In the programmable network system according to the conventional techniques described above, all packets are processed by software using a program loaded at each network node. Therefore, although packets to be processed by software and packets not to be processed are both input to a network node, software processing is performed for both types of the packets so that a process efficiency is not good.